#求出色温
def tem(x,y):
    a = (x-0.329)/(y-0.187)
    t1 = 669*a**4-779*a**3+3360*a**2-7047*a+5652
    b = (x-0.3316)/(y-0.1893)
    t2 = 669*b**4-779*b**3+3360*b**2-7047*b+5210
    if t1<=10000:
        te = t1
    else:
        te = t2
    return te